Usage Of External Cts - LG ESS Home 8 Installation Manual

Usage of External CTs

If the SE Box is unable to measure all house loads under the on-grid status, external site net CTs must
be connected to the energy meter inside the SE Box.
Internal CTs measure the whole current flown into the grid port inside the SE Box, including non-
backup loads connected with the SE Box. According to the site configuration, there are 2 options
for site net measurement by using external CTs. (Please label L1 and L2 at the end of the cables to
prevent them from being switched or use two different cable colors.)
The energy meter inside the SE Box supports a total of 400A (2 x 200A).
With Internal CTs
When adding the current measured by the external CTs to the internal CT measurement is required,
external CTs are used with the internal CTs. Connect the external CT cable to the external CT
connector by using a 4-position terminal block.
Without Internal CTs
If the current is double-measured due to the placement of the external CTs, the internal CTs should
be disconnected.
i) Remove the CT L1, CT L2 connectors from the SE Box.
ii) Insulate the internal CT connectors.
iii) Connect the external CTs as a twisted pair to the external CT connector.
Due to our policy of continuous product innovation, some specifications may change without notice.
©LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. "LG" is a registered trademark of LG Corp.
With Internal CTs
Ext L1
L1 L2
Without Internal CTs
L1
Ext PV
PV L2
Ext PV
L2
Appendix
141